And, unlike a few of his celebrity contemporaries, he has most definitely paid his dues.

In fact, the Apprentice star has revealed he was offered, and turned down, the same tax avoidance schemes which recently landed Gary Barlow and Jimmy Carr in so much hot water.

He says: “I’ve had various schemes thrown at me by various people, and I’ve never been interested. Loads of times I was offered their schemes but I’m a very straightforward thinking person and I keep things nice and straight.

“They come up with all these fascinating schemes which are all allegedly legal and yet the people who bring them to you all then get a fee for doing so. Then off they go and, 10 years later, you find out it was all wrong.

“I try and keep it very simple – pay your tax, that’s it. I’ve been right in the end.”

Take That star Gary, bandmates Howard Donald, Mark Owen and their manager Jonathan Wild now face a hefty one-off tax bill of up to £20million.

Between them they had invested £66million in two partnerships styled as music industry schemes, set up by a firm calling itself Icebreaker Management.

Comedian Jimmy was also forced to apologise earlier this year after it emerged he had paid as little as 1% tax on his earnings through an offshore programme.

After describing it as a “terrible error of judgment”, he now faces a £500,000 tax bill.

“If they’re performers, actors, this, that and the other, and getting loads of money coming in from what they do, and they go to an accountant and say: ‘What do I do?’, and the accountant says, ‘Well, I can save you a bit of tax’. I think they have then said, ‘Fair enough, so long as it’s legal – do it.’

“I think it was ignorance, not stupidity.”

But in stark contrast, Lord Sugar – who was knighted in 2000 for services to business – takes pride in giving back to the economy.

Indeed, the Apprentice chief likes to pin copies on his office wall of the cheques he has paid to the taxman.

One, from his Amstrad heyday in 1989, is for a hefty £48,239,250.

Despite these huge annual payouts to HM Revenue & Customs, Lord Sugar has absolutely no desire to do a Lewis Hamilton, and set up home in Switzerland. For now.

“Would I move? No, no, no, no,” he says. “If tax ever got to 70 or 90%, would I give up work? Yes. Would I leave the country? Yes.

“So whilst it’s at 45%, fair enough. Corporation tax is quite low in this country so that’s quite good.”

Alongside him on the hit BBC1 show panel is Karren Brady, the West Ham vice-chairman who last month was elevated to the House of Lords as a Conservative life peer.

And, in a Parliamentary first, ex-Spurs chairman Lord Sugar will walk the new Baroness Brady into the House.

Warm welcome: Lord Sugar will introduce his Apprerentice pal Karren Brady to the House of Lords (Photo: BBC)

Chatting from an office in London’s Ham Yard Hotel, he explains: “She’s going to be introduced into the House of Lords on November 7, and I’m going to bring her in, which is not normally what’s done.

“You usually have to have two Conservative peers bring her in but I’m doing it as a member of the Opposition. We’re breaking the mould.

“We’re just going to do it – they don’t know we’re doing it, we just are. Well, they will now... the s*** will hit the fan."”

Despite their differences in political opinion, the pair have become good friends on and off the show. Lord Sugar says: “The only rows we have are over Tottenham and West Ham.”

Three years off 70, his enthusiasm for The Apprentice, and life in general, remains strong. This is, in part, down to a diet and exercise regime, one which has helped him shed three stone and, “on a good week”, sees him cycling up to 200 miles.

Two death-defying bike crashes aside – “both times my helmet cracked right down the middle, there was blood everywhere” – the tycoon is a two-wheel fanatic. And fitter than he has ever been.

He muses: “It’s strange: a lot of people of my age actually look better than they did 20 years ago. They let themselves go as young, budding executives and then, as they get older and more relaxed, start looking after themselves again.

I ask Lord Sugar if he moisturises. Again, he grimaces, and sighs: “I don’t moisturise, I don’t use any of that.”

To be fair, he does still have the forehead of a bulldog. He then pauses and, finally, cracks a smile.

“Piers, on the other hand,” he begins. “Well, he’s definitely had his teeth done. And he uses that Just For Men.

“He’s had some work done – take it from me. It’s just a shame his posterior has been growing rather large in recent times...”

With so much Piers-baiting still to be done, it’s little surprise Lord Sugar has no immediate plans to retire.

I earn myself a second grimace and a massive sigh, though, when I ask if he has a target retirement figure in mind – a billion pounds, perhaps?

“It’s a bit silly to talk about things like that,” he snaps. “I don’t like talking about money.”

“Gauche?”, I suggest.

“Yes. Very. Anyway, in American terms, in dollar terms, I’ve been a billionaire for a long time.

“I still consider myself relatively young in business terms, but of course, one day, I can see myself retiring.

“When I think it’s time, I’ll stop doing it – and that may be before the BBC decide they want to stop doing it. I obviously don’t do it for the money, but for the enjoyment. Starting little companies from scratch again, that’s what gives me a buzz.”

He may not have it in mind, but I wouldn’t rule out Lord Sugar making that billion pounds just yet...